The present invention relates to a mobile base and more particularly to a sturdy, economical, adjustable mobile base.
Mobile bases are well known for supporting equipment, for example in a workshop, so that it can be easily moved from place to place within the workshop. A typical mobile base is custom made from metal which is welded together to form a base to fit a specific piece of equipment. The base has a support surface, which receives the bottom of the equipment and wheels to allow the equipment to be easily moved along a shop floor. A locking mechanism or supports are generally provided to hold the base in place once it has been moved to its desired position.
One disadvantage of custom-made mobile bases is the cost. They are designed for the specific tool to be supported, such as a table saw, and are then welded together and shipped to the customer. Their construction is labor intensive, particularly the time required to weld the various elements of the base together. A typical base will have four or more sides welded together at their corners. Further, corner brackets are welded inside of each corner and wheel brackets are welded to side members to receive the wheels. In addition to the labor cost, there are added shipping costs and packaging costs due to the mobile base being a welded unit that is more difficult to ship than one which is capable of being disassembled for shipping purposes.
Another disadvantage with a typical mobile base is that the base is not a do-it-yourself type product. The base requires a design to be established, the various side members and brackets are cut and then welded together to form a sturdy base which can support fairly heavy machinery in a shop environment.
A still further problem with traditional mobile bases is the inability to adjust the base for different types of machinery. Again, the typical mobile base is designed for a specific piece of machinery and can only be used with that specific piece of machinery. It typically cannot be interchanged with other machinery, which, for example, might be purchased to replace existing machinery within a shop environment. If new machinery is purchased, it is likely that it would need to have an entirely new base engineered and manufactured for it.
Attempts have been made to overcome these disadvantages. The applicant developed a universal mobile base known as the Port a Mate that can be adjusted between minimum and maximum sizes. For example, one unit can be adjusted from 12 inches by 17 inches to 25 inches by 30 inches. He has also developed other units that can be adjusted between different minimums and maximums. In this way, a group of bases have been developed which will accommodate machinery in groups of sizes so that a smaller number of bases can be used to support a greater amount of machine sizes.
This Port a Mate has corner members made of hollow square tubing welded to form a corner of about 90 degrees. Support plates are welded to the corner brackets for supporting the machinery. Wheel mounting brackets are also welded to three of the four corners. The sides of the base are formed by square tubing that is received within the corner tubing. The corner tubing has bolts that can be threaded into the corner tubing to engage the square tubing and hold it within the corner tubing. The corner tubing is open on both ends so that the square tubing can slide through the corner tubing to adjust the dimensions of the mobile base member between the minimums and maximums.
One difficulty with the mobile base is that it is still expensive to manufacture because the corner tubing has to be welded together, the wheel brackets have to be welded onto the corner brackets, and the corner support plates must be welded to the corner tubing. Further, the side members must be cut once the desired shape is determined so that the square side tubing is not extending out beyond the corner members.
Delta International Machinery Corporation has also attempted to solve the above problems by manufacturing a universal mobile base that can be assembled by do-it-yourselfers. The product includes corner brackets, wheels, a caster assembly, a foot pedal and assembly hardware. The base has four corner brackets that include corner support members and two of the corner members include caster wheels. Opposite the caster wheels is a caster wheel assembly that is mounted to a side member. The caster wheel assembly allows the side member opposite the caster wheels to be raised so that it can be moved around a shop floor. The caster wheel assembly includes a foot pedal that permits a user to press down on the foot pedal to raise the mobile base for moving. The side members of the Delta mobile base are made of wood and are received within the corner members and bolted in place.
A major problem with the universal mobile base is the use of the wood side rails. These rails must be sized, that is machined from a 2.times.4 to a 2.times.2, and cut to their desired length, holes drilled in them and bolts inserted to hold them in place. Although these tasks are well within the means of a typical do-it-yourselfer, it is time-consuming to construct the Delta mobile base. Further, because the rails are made of wood, there is a possibility of warping and rotting. Depending upon the environment in which the mobile base is used, the wood could warp and even over time rot requiring replacement so that the machinery can be properly supported upon the mobile base.